Question

The electrostatic potential on the surface of uniformly charged spherical shell of radius R = 10 cm is 120 V. The potential at the centre of shell, at a distance 5 cm from centre and a distance 15 cm from the centre of the shells are :-

(1) 0V, 120 V, 40 V

(2) 40 V, 40 V, 80 V

(3) 120 V, 120 V, 80 V

(4) 0 V, 0 V, 80 V

Answer 1

Correct option is : (3) 120 V, 120 V, 80

\(V_{\text{surface}} = \frac{KQ}{R} = 120 = (V_{in})_{\text{surface}}\)

\(v_c = 120 V\) 

\(v_{5cm} = 120 V\)

\(v_{15} = \frac{kQ}{r} = 120 \times \frac{10}{15}= 80\)